Table 1.
Functional properties of AMPARs in neurons of the basal ganglia
| Cell type | Deactivation τ (msec) | Desensitization τ (msec) | PCa/PNa | Rectification index (g+40mV/g−80mV) | Peak current NP, −60 mV (pA) |
|---|---|---|---|---|---|
| Striatum | |||||
| Striatal principal neurons | 2.2 ± 0.1 (10) | 11.5 ± 0.9 (10) | 0.11 ± 0.00 (9) | 0.93 ± 0.02 (9) | 692 ± 95 (9) |
| Striatal cholinergic interneurons | 1.2 ± 0.1 (10) | 3.6 ± 0.4 (10) | 1.16 ± 0.16 (10) | 0.49 ± 0.06 (10) | 246 ± 18 (10) |
| Substantia nigra | |||||
| Nigral GABAergic neurons | 1.7 ± 0.2 (8) | 3.6 ± 0.3 (9) | 0.11 ± 0.01 (8) | 1.08 ± 0.17 (7) | 326 ± 46 (7) |
| Nigral dopaminergic neurons | 1.6 ± 0.1 (8) | 6.1 ± 0.8 (9) | 0.10 ± 0.01 (6) | 1.01 ± 0.07 (7) | 571 ± 90 (7) |
| Globus pallidus and subthalamic nucleus | |||||
| Globus pallidus neurons | 1.1 ± 0.1 (5) | 5.1 ± 0.8 (5) | 0.67 ± 0.14 (7) | 0.70 ± 0.06 (7) | 166 ± 60 (7) |
| Subthalamic nucleus neurons | 1.6 ± 0.1 (8) | 3.6 ± 0.4 (9) | 1.17 ± 0.30 (6) | 0.60 ± 0.06 (6) | 285 ± 60 (6) |
Deactivation and desensitization time constants of AMPARs were determined using 1 and 100 msec pulses of glutamate, respectively. ThePCa/PNa of AMPARs was calculated from the shift of reversal potential of glutamate-activated currents on exchange of Na+-rich by Ca2+-rich (30 mm) external solution. The rectification index of the AMPAR-mediated current,g+40mV/g−80mV, was determined in Na+-rich external solution. The peak current amplitude at −60 mV was determined in Na+-rich external solution. All data were obtained from nucleated patches (NP) using 3 mm glutamate, with the exception of AMPAR kinetics, which was studied in outside-out patches using 1 mm glutamate.